In sociology and economics, as well as in common political discourse, social mobility refers to the degree to which an individual or group's status is able to change in terms of position in the social hierarchy. To this extent it most commonly refers to material wealth and the ability of an agent to move up the class system. Such a change may be described as "vertical mobility," by contrast with a more general change in position ("horizontal mobility"). Mobility is enabled in part by cultural capital (such as higher education or an authoritative accent), human capital (such as competence and effort in labour), social capital (such as support from one's social network), physical capital (such as ownership of tools), and symbolic capital (such as the worth of an official title). Many of these factors, however, ultimately remain intertwined with economic capital. Policy issues, such as welfare or the existence of public transport, may exercise significant influence. Geographical factors may also be of importance. The extent to which a nation is open and meritocratic is of fundamental significance: a society in which traditional or religious caste systems dominate is unlikely to present the opportunity for social mobility.